Many medical procedures involve the precise placement of medical needles. In some medical procedures, it is desirable to place a needle into or on a specified portion of a patient's body by guiding the needle with the assistance of X-ray. For example, a discogram involves the precise placement of a needle directed by the assistance of an X-ray device or fluoroscope.
If a patient experiences pain that the physician believes to be caused by a patient's intervertebral disc, the disc may be studied by discogram, which is a procedure that entails placing a needle through the annulus fibrosus and into the nucleus pulposus of the disc. The discogram procedure is used to study the disc by injecting a radiopaque dye into the disc to study the integrity of the disc and to reproduce the patient's pain response. In performing cervical discograms, a real-time X-ray or fluoroscope is used during the procedure to allow the physician or health care provider to accurately place the needle without passing it through tissue, veins, or arteries,or nerves that might be harmful to the patient.
The discogram procedure has required the physician to use his or her hand in the primary X-ray field. In this procedure, a cervical disc may be approached from the anterior side. The physician or health care provider uses his or her index finger on the left hand (for a right-handed physician) to firmly press between the esophagus and the carotid sheath. This pressure is to locate and move as necessary the carotid artery, jugular vein, esophagus and other tissue. The discogram needle is then inserted just below the physician's left index finger. Once the needle is inserted, the fluoroscope or X-ray equipment is activated. The width of the finger separates the lateral/medial structures and under direct fluoroscopic control, the finger is used to guide the needle first to the vertebral body and then to the annulus fibrosus. The needle is then passed directly into the disc, but must not be passed through the disc. To gauge the depth of the needle, the physician advances the needle using fluoroscopy in the posterior-anterior projection and the lateral projection. The physician must spend considerable time in guiding the needle under the fluoroscope because of the potential harm of a misaligned needle; to perform this procedure, the physician may have his or her hand in the primary X-ray field for as long as ten minutes to an hour.
This technique of using one's finger to probe and guide a medical needle during a discogram has several shortcomings. First, the physician is exposed to a significant amount of radiation during the procedure. Second, the physician must place the needle against his or her index finger which increases the likelihood that the needle will puncture the physician's glove or even the physician's skin. Puncturing the physician's glove can be a serious threat to the patient because it increases the possibility that infectious contaminants may be carried into the body and particularly into the nucleus pulposus of the patient's disc, which can generate life threatening complications. Puncturing the physician's skin is dangerous because of the proliferation of the HIV virus and other diseases that may be transmitted by body fluids such as blood. Finally, the physician's finger does not make a good pointer during fluoroscopic procedures because it is not radiopaque as such.
Therefore, a need has arisen for a surgical X-ray instrument for use during medical procedures involving radiation that allows the physician to not have his hand in the primary radiation field, that reduces the risk of unwanted glove or skin puncture, and facilitates locating the needle during procedures.